[c-nsp] Where do you put the optical attenuators?

[Tassos Chatzithomaoglou]

Does anyone know if in-line optical attenuator have to be connected on the receiver side only?

For example in the following link


    A---------------------C
SW1                      SW2
    B---------------------D

SW1 is transmitting through A and receiving through B
SW2 is transmitting through D and receiving through C

Where is the best place to put the attenuators? B & C?
Can i put them on A & B?

I did some tests putting them on every possible side (as long as there is one on each fiber strand) and all of them worked, but i 
was wondering if there is a best practice about them.

-- 
Tassos